1. VOUT1, 1.8V
ADJUSTABLE
UP TO 9A
CINH
22µF
×3
CINL
220µF
10k
×9
VIN*
5.75V TO 17V
PWM CLOCK SYNCH.
TIME BASE SYNCH.
• SLAVE ADDRESS = 1001111_R/W (0X4F)
• SWITCHING FREQUENCY: 500kHz
• NO GUI CONFIGURATION AND
NO PART SPECIFIC PROGRAMMING REQUIRED
IN MULTI-MODULE SYSTEMS, CONFIGURING
RAIL_ADDRESS IS RECOMMENDED
*FOR VIN ≤ 5V, SET:
VIN_OFF < VIN_UV_WARN_LIMIT < VIN_ON < 4.3V
COUT0
100µF
×4
COUT1
100µF
×4
VOUT0, 1.0V
ADJUSTABLE
UP TO 9A
VIN0
VIN1
SVIN
VDD33
LOAD0SCL
SDA
ALERT
RUN0
RUN1
GPIO0
GPIO1
SYNC
SHARE_CLK
ASEL
FSWPHCFG
VOUT0CFG
VTRIM0CFG
VOUT1CFG
VTRIM1CFG
INTVCC
VDD25
SW0
SW1
COMP0a
COMP0b
COMP1a
COMP1b
GND
WP
6.34k
1%
±50ppm/°C
LTM4675
dn4jym F01
+
SMBus INTERFACE WITH
PMBus COMMAND SET
ON/OFF CONTROL, FAULT
MANAGEMENT, POWER
SEQUENCING
LOAD1
VOUT0
TSNS0
VORB0
+
VOSNS0
+
VOSNS0
–
VORB0
–
VORB1
VOUT1
TSNS1a
TSNS1b
VOSNS1
SGND
Dual 9A, Step-Down µModule Regulator with Digital Power
System Management
Design Note 542
Jian Li, Yingyi Yan and Marvin Macairan
09/15/542
Introduction
The LTM4675 is a dual 9A or single 18A step-down
µModule®
(micromodule) DC/DC regulator featuring
remote configurability and telemetry monitoring of
power system management (PSM) parameters over
PMBus—an open standard I2C-based digital inter-
face protocol. Its 16mm × 11.9mm × 3.51mm BGA
package includes analog control loops, precision
mixed-signal circuitry, EEPROM, power MOSFETs,
inductors and supporting components. It features a
wide 4.5V to 17V input voltage range, and a 0.5V to
5.5V output voltage range with ±0.5% DC accuracy
over temperature. LTM4675’s power outputs can be
digitally adjusted, margined and powered up/down
at programmable slew rates and sequencing delay
times. Maximum turn-on time is 70ms. Telemetry
read back parameters include VIN, IIN, VOUT, IOUT,
temperature, running peak values, uptime, faults and
warnings. Current read back accuracy is ±2.5% at 9A
load over temperature.
TheLTM4675facilitatesthedesignofhighefficiency,
high power density and high reliability solutions for
telecom,datacomandstoragesystems,plusindustrial
andinstrumentationpowersupplies.TheLTM4675is
offered in a 16mm × 11.9mm × 3.51mm BGA package
availablewithSnPborRoHScompliantterminalfinish.
Dual 9A µModule Regulator with Digital Power
System Management
Figure 1 shows a typical LTM4675 application. The
input voltage range is 5.75V to 17V, and the outputs
are 1V/9A and 1.8V/9A. Figure 2 shows the efficiency
L, LT, LTC, LTM, Linear Technology, the Linear logo and µModule are
registered trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
Figure 1. 9A, 1V and 9A, 1.8V Output DC/DC µModule Regulator with Serial Interface

2. LOAD CURRENT (A)
0
EFFICIENCY(%)
95
90
80
70
85
75
65
60
4 82 6
dn4jym F02
93 71 5
VO = 2.5V, 650kHz
VO = 1.5V, 575kHz
VO = 1.0V, 500kHz
VO = 3.3V, 650kHz
VO = 1.8V, 650kHz
VO = 1.2V, 500kHz
VO = 0.9V, 425kHz
LINEAR TECHNOLOGY CORPORATION 2015
dn542f LT/AP 0915 111K REV A • PRINTED IN THE USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
foreachoutputoftheLTM4675foravarietyofoutput
voltages vs load current. The LTM4675 can achieve
high efficiency over a wide operating range, with
high reliability. Figure 3 shows that the maximum
case temperature is 84.1°C when the module is run-
ning with a 12V input, 1V/9A and 1.8V/9A outputs,
without airflow.
running peak values, uptime, faults, warnings and
an onboard EEPROM fault log record. Writable data
and configurable parameters include output voltage,
voltagesequencingandmargining,digitalsoft-start/
stopramp,OV/UV/OT,UVLO,frequencyandphasing.
The LTM4675 guarantees high accuracy telemetry
read back with an integrated 16-bit ∆∑ ADC.
Multi-Module Operation for High Current
Applications
The LTM4675 utilizes a constant frequency peak
current mode control architecture, which enables
cycle-by-cycle current limit and easy current sharing
among phases when the channels are operated in
parallel.Forhigheroutputcurrentcapability,it’seasy
to parallel multiple LTM4675 modules. Furthermore,
the LTM4675 can be used as a master to drive non-
PSM power modules to provide much higher output
current. For example, the LTM4675 can drive three
LTM4630s to provide up to 125A output current.
Figure4showsthethermalpictureofthisapplication.
With 400LFM of airflow, the hot spot temperature
rise is only 66.2°C. The uniform thermal distribu-
tion among the modules is due to excellent current
sharing performance.
Data Sheet Download
www.linear.com/LTM4675
For applications help,
call (408) 432-1900
Figure 2. LTM4675 Single Channel Efficiency
at VIN = 12V
Figure 3. Thermal Performance of LTM4675
at VIN = 12V, VOUT0 = 1V/9A, VOUT1 = 1.8V/9A,
No Airflow, Tested on DC2053A. Maximum
Temperature Rise = 61.1°C, TA = 23°C
Figure 4. Thermal Picture at VIN = 12V, VO = 1.0V/125A,
400LFM Airflow, Maximum Temperature Rise = 66.2°C,
TA = 23°C
TheLTM4675offersinternalcompensationorexternal
compensation, which can be used to optimize the
transient response to load current steps over a wide
operating range.
The LTM4675 supports a PMBus-compliant SMBus
serialinterfaceupto400kHz.Readabledataincludes
input and output voltages, currents, temperatures,
Conclusion
LTM4675 is a high efficiency and high power density
µModule regulator with built-in digital power system
management. With all of the features mentioned
above, the LTM4675 is ideal for telecom, datacom
and storage systems, industrial and instrumentation
applications.